Generally, an unmanned aerial vehicle (UAV) refers to an air vehicle capable of autonomously flying without a pilot according to a previously input program or through self-recognition of surrounding environments (such as obstacles and airplanes).
The unmanned aerial vehicle generally carries out high altitude long endurance missions for observation, monitoring, communication relay, weather observation, earth observation, and the like. Such an unmanned aerial vehicle employs power supplied from charged batteries.
Particularly, in a wireless charging method by which an unmanned aerial vehicle is wirelessly charged, a magnetic flux is generated around a magnetic flux transmit coil by supplying electric current to the transmit coil such that a reception coil placed near the transmit coil receives the magnetic flux and induces electric current.
However, such magnetic induction has a problem in that charging efficiency significantly differs depending upon a positional relationship between the transmit coil and the reception coil.
In order to solve this problem, conventionally, a magnet is provided to each of a transmit coil and a reception coil of a wireless charging device such that coupling between the transmit coil and the reception coil can be improved through magnetic force between the magnets thereof, or the wireless charging device is provided with a plurality of transmit coils.
However, a charging method using magnets has problems in that the reception coil must be placed within the range of magnetic force, and in that the coils are likely to be broken or damaged when frequently moved.
Moreover, a charging method using a plurality of transmit coils has problems of high manufacturing costs and low charging efficiency.
The background technique of the invention is disclosed in Korean Patent Registration No. 1,194,676 (issue date: 2012 Dec. 19) entitled “Wireless servo actuator capable of performing position control in up-down and right-left directions in wireless remote control type”.